A hydraulic work machine is equipped with a hydraulic breaker attached to the distal end of a work equipment that is mounted on the machine body in such a manner as to be capable of moving vertically. The hydraulic breaker is provided with a hydraulic hammer mechanism that does not require flow rate adjusting operation at the machine body (e.g. see Japanese Laid-open Patent Publication No. 5-185378 (p 1, and FIG. 1)).
The operation procedure for crushing an object to be crushed by means of a hammer of a hydraulic breaker of this type includes steps in the order of first positioning the distal end of the hammer on the object to be crushed; subsequently raising the machine body relative to the hammer by operating the lever that serves to vertically move the boom of the work equipment so as to lower the boom and press the hammer against the object to be crushed; then, by operating a switch or other similar element, starting striking operation of the hammer while applying the load of the machine body to the object to be crushed through the end of the hammer; and, when the object is crushed, returning the switch or other similar element to the neutral position, thereby completing the striking operation.
At that time, it is necessary to operate the switch or other similar element while adjusting the load applied to the object to be crushed during a boom-down operation. This operation not only requires the operator to have sophisticated skills, but also causes the operator to become greatly fatigued.
To be more specific, as striking in the state where no load is applied to the hammer causes blank firing, which results in damage to the hammer, it is necessary to finish striking immediately when the object to be crushed is demolished. Even a skilled operator, however, is prone to a slight delay in actually shifting the switch or other similar element to the neutral position after the object is demolished and thereby causing a blank firing.
In order to solve the above problems, an object of the invention is to provide a work machine equipped with an automatic hammering function that is easy to operate and capable of preventing breakage of the hammer caused by blank firing.